Large-scale nomothetic prevention programs aimed at providing accurate, factual-based information regarding HIV risk have led to a greater awareness of HIV/AIDS risks; however, these programs have had relatively limited success in preventing or reducing engagement in HIV-related risk taking behaviors among adolescents. More recent individualized, skill-based prevention programs have led to a reduction in HIV-related risk taking behaviors as well as incidence of actual infection, but individualized programs can be costly and may be difficult integrate into community settings. Thus, recent work has aimed to identify and targeting adolescents most at risk for HIV infection, based on their unique vulnerabilities. Typically, researchers have relied exclusively on self-report instruments to determine vulnerability for engagement in HIV-relevant risk behaviors, but these approaches have several limitations, and their success in identifying at-risk adolescents has been limited. As an alternative approach, the Balloon Analogue Risk Task-Youth (BART; BART-Y) can be used to assess risk taking propensity in an objective and less transparent manner than self-report scales. This approach has shown strong cross-sectional relationships with risk behavior, but little has been done examining the utility of the approach for prospective identification of at-risk youth. Towards this end, R01 DA18647 was funded to provide the first longitudinal test of the BART. We were able to successfully recruit 277 youth (age 10-12) and their families into a baseline assessment; participants were on average 11.0 (SD = .81) years old, 43.7% female, 49.3% White, 35.5% Black, 2.9% Hispanic, 1.4% Asian/Pacific Islander, and 10.9% of mixed or other ethnicity. Follow-up rates have been excellent, with 89% of youth at Year 2, and only an additional drop of 2% to 87% of youth at Year 3 completing assessments. Throughout the project period, supplementary funds were secured to expand: 1) the sample with another 400 10-12 year olds, 2) the theoretical perspective to include behavioral measurement of negative reinforcement related risk taking, and 3) the breadth of the assessment to include targeted genetic markers as well as in-vivo assessment of environmental context to provide a novel assessment of gene x environmental vulnerability to risk taking. As outlined in the current application we have strong findings thus far and we propose another 5 year period of support to provide for the continuation of this work as the youth are progressing into a period where HIV risk behavior will begin to peak.